scientific-2014

Scientific papers 2014

Bruce Wienke (1940 - 2020) was the Program Manager in the United States of America Nuclear Weapons Technology Simulation And Computing Office at the Los Alamos National Laboratory. He worked on decompression, gas transport, and phase mechanics. He published numerous documents related to decompression models and contributed to many workshops. He also developed algorithms for decompression computers, notably those used by the brand “Suunto”. In this article, he made a status of the existing decompression models used for diving applications and their impact on these activities.

18 - J. K. Tatuene, R. Pignel, P. Pollak, K.O. Lovblad, A. Kleinschmidt, & M.I. Vargas: Neuroimaging of diving-related decompression illness: Current knowledge and perspectives.

Magnetic Resonance Imaging (MRI) is currently the most accurate neuroimaging technique available for detecting brain and spinal cord lesions in neurologic type 2 decompression sickness. Some typical results are summarized and illustrated in this article. Also, the authors review the limitations of previous work and make practical methodologic suggestions for future neuroimaging studies.

Authors: Antonino Baez, Joseph Shiloach, Tadeusz Doboszynski. The response of bacteria, yeast, and mammalian and insects cells to oxidative stress is a topic that has been studied for many years. However, in most reported studies, the oxidative stress was caused by challenging the organisms with H2 O2 and redox-cycling drugs but not by subjecting the cells to high concentrations of molecular oxygen. In this review, the authors summarize the available information about the effect of elevated oxygen concentrations on the physiology of microorganisms and cells at various culture conditions.

Authors: Danilo Cialoni, Massimo Pieri, Costantino Balestra, and Alessandro Marroni, Introduction: Flying after diving may increase decompression sickness risk (DCS), but strong evidence indicating minimum prefight surface intervals (PFSI) is missing. Methods: On return flights after a diving week on a live-aboard, 32 divers were examined by in-flight echocardiography with the following protocol: outgoing flight, no previous dive; during the diving week; before the return flight after a 24- h PFSI; and during the return flight.

Authors: Lesley Blogg, Mikael Gennser, Andreas Møllerløkken, and Alf O Brubakk Introduction: Diving often causes the formation of ‘silent’ bubbles upon decompression. If the bubble load is high, then the risk of decompression sickness (DCS) and the number of bubbles that could cross to the arterial circulation via a pulmonary shunt or patent foramen ovale increase. Bubbles can be monitored aurally, with Doppler ultrasound, or visually, with two-dimensional (2D) ultrasound imaging. Doppler grades and imaging grades can be compared with good agreement. Early 2D imaging units did not provide such comprehensive observations as Doppler, but advances in technology have allowed the development of improved, portable, relatively inexpensive units. Most now employ harmonic technology; it was suggested that this could allow previously undetectable bubbles to be observed.

Authors: Emmanuel Gempp, Pierre Louge, Sébastien De Maistre, Loïc Emile and Jean-Eric Blatteau. Neuron-specific enolase (NSE) and S100B protein are brain-origin proteins commonly described to assess the presence and severity of the neurological injury. To date, limited data are examining the influence of scuba diving on these biomarkers, particularly when symptoms of decompression sickness (DCS) occur. The purpose of this controlled study was to determine whether these serum neurochemical markers could be used as indicators of neurological DCS and predictors of incomplete recovery.

Authors: Abu Shamsuzzaman, Michael J. Ackerman, Fatima Sert Kuniyoshi, Valentina Accurso, Diane Davison, Raouf S. Amin, and Virend K. Somers. This study aimed to develop a simple and practical method for simulating diving in humans using facial cold exposure and apnea stimuli to measure neural and circulatory responses during the stimulated diving reflex.

Authors: Damien Fouan, Younes Achaoui, and Serge Mensah. A microbubble sizing method based on the odd harmonics of square-like excitations is presented. The microbubble resonance signature is determined by measuring the backscattered signals using the Dual Frequency Method combined with a time-frequency representation. This method's efficiency and limitations are described in the case of sine-like excitations.

Authors: Stephen R. Thom, Veena M. Bhopale, and Ming Yang. Microparticles are generated in vivo with exposures to high-pressure gases by unclear mechanisms. As a result, high inert gas pressure causes singlet oxygen formation, which initiates a cycle of actin S-nitrosylation, nitric-oxide synthase-2, and NADPH oxidase activation leading to microparticle formation. In conclusion, Inert gas-mediated oxidative stress causes microparticle production, which may initiate events leading to decompression sickness.

Authors: Virginie Papadopoulou, Meng-Xing Tang, Costantino Balestra, Robert J. Eckersley, Thodoris D. Karapantsios. In contrast to decompression-induced bubbles, whose site of initial formation and exact composition are debated, there are other instances of bubbles in the bloodstream which are well-defined. Gas emboli unwillingly introduced during surgical procedures and ultrasound microbubbles injected for use as contrast or drug delivery agents are therefore also discussed. After presenting the different ways that bubbles can end up in the human bloodstream, the general mathematical formalism related to the physics of bubble growth and detachment from decompression is reviewed. .

Authors: Jason M. Valadao, John A. Vigilante, Nicholas W. DiGeorge, Sunila E. O’Connor, Alexandria Bear, Jeffrey Kenyon, Heather Annis, Joseph Dituri, Amy E. Dituri, Harry T. Whelan. A ketogenic diet (KD) may decrease central nervous system oxygen toxicity symptoms in divers. In view of this implication, a feasibility/toxicity pilot study was performed to demonstrate tolerance of KD while performing normal diving profiles. .

Authors: Pieter-Jan Van Ooij, R.A. van Hulst, W. Kulik, P. Brinkman, A. Houtkooper, P.J. Sterk Exhaled breath contains volatile organic compounds (VOCs) associated with respiratory pathophysiology. The authors hypothesized that hyperbaric oxygen exposure (hyperoxia) generates a different VOC pattern. This study aimed to test this hypothesis in oxygen- breathing divers.

Authors: Antonio Ayala, Mario F. Muñoz, and Sandro Argüelles Lipid peroxidation can be described as a process under which oxidants such as free radicals attack lipids containing carbon-carbon double bond(s), especially polyunsaturated fatty acids. Extensive literature regarding lipid peroxidation has shown its essential role in cell biology and human health. Discoveries about the involvement in cellular physiology and pathology, as well as the control of lipid peroxidation, continue to emerge every day.

Publisher: Undersea and Hyperbaric Medical Society This document from the Undersea and Hyperbaric Medical Society , published in 2014, provides guidance and support for scientists and practitioners of hyperbaric oxygen therapy.

Authors: Romuald Olszanski, Piotr Radziwon, Jolanta Korsak, Piotr Siermontowski, Mariusz Kozakiewicz Gas bubbles occurring during decompression create a non-physiological surface that comes into contact with blood platelets and coagulation proteins. The result is the activation of blood platelets and contact factors. Accordingly, over 30 years ago, Polish researchers began verifying the safety of decompression tables by evaluating changes in homeostasis and fibrinolysis.

Authors: Christopher Matthew Norton Earing, Damian John McKeon, Hans-Peter Kubis Two studies were performed to investigate the ventilatory response to CO 2 in hyperoxia, hypoxia, and during exercise amongst experienced scuba divers and matched controls. The first investigated the CO2 sensitivity in rest and exercise using CO2 rebreathing in hyperoxia at a workload typical for diving with divers and controls. The second study examined the respiratory drive of divers and controls whilst breathing four different gas mixtures balanced with N2 to assess the combined response to hypercapnia and moderate hypoxia.

Authors: Richard E. Moon, Simon Mitchell The use of oxygen with pressure to accelerate gas diffusion and bubble resolution in humans was first suggested in 1897 and eventually tested in the 1930s for human DCS and recommended for treatment of divers. It is also likely that hyperbaric O2 has other beneficial pharmacological effects such as a reduction in neutrophil adhesion to the capillary endothelium. The efficacy of hyperbaric O2 is now widely accepted, and is the main stay of treatment for this disease.

Authors: J.C. Rostain, N. Balon Compressed air or a nitrogen-oxygen mixture produces from 0.3MPa nitrogen narcosis. The traditional view was that anaesthesia or narcosis occurs when the volume of a hydrophobic site is caused to expand beyond a critical amount by the absorption of molecules of a narcotic gas. The observation of the pressure reversal effect on general anaesthesia has for a long time supported the lipid theory. However, recently, protein theories are in increasing consideration since results have been interpreted as evidence for a direct anaesthetic-protein interaction.

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Authors: J.G. Swan, J.C. Wilbur, K.L. Moodie, S.A. Kane, D.A. Knaus, S.D. Phillips, T.L. Beach, A.M. Fellows, P. J. Magari, and J. C. Buckey This study aimed to determine whether microbubbles could be found in blood vessels and if they preceded larger venous gas embolisms (VGE). Fifteen anesthetized pigs underwent a 2-hour high-pressure exposure, followed by decompression. Results showed that microbubbles appeared in the bloodstream immediately after decompression, with or without VGE. Without VGE, microbubbles persisted throughout the hour, whereas with VGE, they initially appeared but dissipated. No microbubbles were observed in the control sham dives.

Authors: Konstantinos Tasios, Georgios G Sidiras, Vasileios Kalentzos and Athina Pyrpasopoulou A probable case of decompression sickness with skin mottling improved with oxygen and treatment, but the patient was later transferred for specialized care. Although skin symptoms are not typically fatal, prompt identification is crucial as they may indicate significant risks. An allergic reaction is also a potential diagnosis in this case.

7 - Sample size requirement for comparison of decompression outcomes using ultrasonically detected venous gas emboli (VGE): power calculations using Monte Carlo resampling from real data.

Authors: David J Doolette, Keith A Gault, and Christian R Gutvik Studies that use venous gas emboli (VGE) as an outcome measure require careful design to ensure adequate power to detect significant differences. A comparison of two decompression schedules indicated a link between VGE grades and decompression sickness (DCS) incidence, emphasizing the importance of sample size. The results showed that a minimum of 50 subjects are needed to achieve about 80% power, while fewer than 30 subjects significantly reduce power below 50%. Thus, comparisons made with fewer than 30 subjects should be approached cautiously, and a sample size of 50 is recommended for robust study results.

Authors: Peter Germonpré, Virginie Papadopoulou, Walter Hemelryck, Georges Obeid, Pierre Lafère, Robert J Eckersley, Ming-Xing Tang and Costantino Balestra Decompression stress is typically assessed by counting bubbles in the bloodstream after a dive using Doppler or cardiac echography. This data helps develop safer decompression practices by linking fewer bubbles to a reduced risk of decompression sickness. The researchers considered that the Eftedal and Brubakk method for evaluating these bubbles has limitations and introduced a new "frame-based" counting method that provides a continuous measurement scale.

Authors: Philippa Welfare, Mark Little, Peter Pereira, and Jamie Seymour This study aimed to determine the effects of acetic acid (vinegar) on the release of nematocysts during a simulated sting caused by Chironex fleckeri (also known as the box jellyfish). The results suggest that vinegar promotes the further release of venom from nematocysts that were previously discharged. This raises concerns that vinegar may be harmful as a first-aid treatment for Chironex fleckeri stings.

Author: Ross Di Colerto Staying hydrated is crucial for managing heat-related illnesses. Measuring individual fluid levels is helpful in assessing heat stress. Traditionally, this involves weighing someone before and after exposure to determine fluid loss, although it's not always convenient and requires ongoing record-keeping. Nowadays, measuring urine specific gravity (SG) has become a popular method for monitoring hydration. But how accurate and effective is this method for managing heat stress?

Authors: Zeljko Dujk, Davor Eterovic, Pero Denoble, Goran Krstacic, Jadranka Tocilj A rebreathing method has been developed to measure the lung's diffusing capacity for carbon monoxide (DCO) in hyperbaric conditions. The study included 22 naval divers with normal lung function. Strong correlations were found between rebreathing and single-breath measurements for DCO, alveolar volume (VA), and DCO/VA. Measurements were taken before, during, and after a dive in a controlled environment, following the US Navy decompression protocols.

Publisher: Sami F. Khalil, Mas S. Mohktar, Fatimah Ibrahim This paper explores various bioimpedance measurement techniques, including frequency-based, allocation-based, vector analysis, and real-time systems. The method discusses prediction equations for body composition, taking into account factors such as anthropometry, gender, ethnicity, posture, protocol, and electrode artifacts. Additionally, the paper addresses bioimpedance's role in detecting abnormal lean mass loss and fluid imbalances and its diagnostic applications in cardiac, pulmonary, renal, neural, and infectious diseases.

Authors: M. Gronning, J. Risberg, H. Skeidsvoll, G. Moen, L. Aanderud, K. Troland, E. Sundal, E. Thorsen This study evaluated the effectiveness of electroencephalography (EEG) and magnetic resonance imaging (MRI) in diagnosing acute decompression sickness (DCS) in the central nervous system (CNS). It determined the utility of these diagnostic tools in clinical settings and concluded that both EEG and MRI have low sensitivity for diagnosing acute DCS in the CNS. The study authors also suggest that recompression treatment for DCS should continue to be guided primarily by clinical neurological examinations and symptom assessments.

Author: Peter Buzzacott, Aleksandra Mazur, Qiong Wang, Kate Lambrechts, Michael Theron, Jacques Mansourati, and François Guerrero. This paper discusses the findings of a study that evaluated the reliability of using a tilting-board grip score to measure decompression sickness in rats. The study involved a hyperbaric compression/decompression protocol, observations for signs of decompression sickness, and their grip strength measured on a tilting particle board hinged to a metal frame. The results indicated a significant association between decreased grip scores and the probability of decompression sickness, suggesting that the tilting-board grip score is reliable for assessing decompression sickness in rats.

Authors: Ian C Gawthrope, David A Playford, Benjamin King, Kathryn Brown, Catherine Wilson and Barry McKeown This study evaluated the cardiac changes occurring during hyperbaric oxygen (HBO) therapy using transthoracic echocardiography (TTE) in subjects without active cardiac disease and determined whether HBO has adverse effects on cardiac physiology. It concluded that TTE can be safely performed within a hyperbaric chamber and that HBO does not adversely affect cardiac physiology in individuals without active cardiac disease.

24 - Retrospective review of grommet procedures under general versus local anaesthesia among patients undergoing hyperbaric oxygen Therapy

Authors: Laura Lamprell, Derelle Young, Venkat Vangaveti, John Orton and Anand Suruliraj This paper presents a study that investigates the differences between patients receiving hyperbaric oxygen treatment (HBOT) and concurrent grommet insertion under local anesthesia (LA) versus general anesthesia (GA) at The Townsville Hospital (TTH). It compares the safety, timing, and outcomes of grommet insertion under these two types of anesthesia in the context of HBOT- associated middle ear barotrauma (MEBT).

Authors: David R Smart, Corry Van den Broek, Ron Nishi, David Cooper and David Eastman This study assessed the risk factors for decompression illness (DCI) among aquaculture divers in Tasmania. It aimed to determine if repetitive, short-duration bounce dives (yo-yo dives) were a risk factor for DCI, identify dive profiles with acceptable risk, and investigate ways to improve productivity. The results indicated that bounce diving was not a major factor causing DCI, and the analysis led to improved industry productivity by increasing the permissible number of bounces without compromising safety. The study also provided recommended guidelines for bounce diving to a depth of 21 msw.

Authors: Rasool Zarezadeh and Mohammad Ali Azarbayjani This study investigated the effects of environmental pressure changes with depth on serum cortisol levels in the body. It specifically examined how cortisol levels change after air scuba dives at various depths in open water. The text details the methodology, results, and conclusion of the study, highlighting that cortisol levels increased with immersion and were significantly higher at greater depths. This suggests that these changes are due to the physiological effects of immersion and increased environmental pressure.

Authors: Natalie A. Masento, Mark Golightly, David T. Field, Laurie T. Butler and Carien M. van Reekum This document reviews and integrates recent research findings on the effects of water consumption and dehydration on cognitive abilities and mood. It highlights the positive influence of water on brain function, particularly in vulnerable populations like the elderly and children. The text also seeks to identify methodological weaknesses in current studies and suggest future research directions to understand better the mechanisms by which water affects brain health and function.

Authors: Costantino Balestra This document discusses the potential mechanisms and pathways for the formation and transport of microbubbles in the body following decompression. It examines various hypotheses about where and how these microbubbles form, proposing the lymphatic system as a possible transport mechanism that could explain the detection of vascular gas emboli over extended periods. Additionally, it refers to findings and studies related to preventing decompression sickness, suggesting that whole-body vibration before a dive may reduce post-dive bubble formation through mechanical dislodgement or enhanced lymphatic elimination of gas nuclei.

Authors: R. Arieli, A. Marmur The aim of this paper is to present scientific observations and findings related to the formation and behavior of nanobubbles and gas micronuclei on hydrophobic surfaces and ovine blood vessels during decompression. It highlights a new discovery of active spots where bubbles nucleate and suggests the need for further exploration of the potential neurological effects of large arterial bubbles.